Background: The Mental Health Continuum-Short Form (MHC-SF) is a measure of positive mental health and flourishing, which is widely used in several countries but has not yet been validated in Denmark. This study aimed to examine its qualitative and quantitative properties in a Danish population sample and compare scores with Canada and the Netherlands. Methods: Three thousand five hundred eight participants aged 16-95 filled out an electronic survey. Both the unidimensional and multidimensional aspects of the Danish MHC-SF were studied through bifactor modelling. Cognitive interviews examined face validity and usability. Results: The general score of the Danish MHC-SF was reliable for computing unit-weighted composite scores, as well as using a bifactor model to compute general factor scores or measurement models in an SEM context. Nonetheless, subscale scores were unreliable, explaining very low variance beyond that explained by the general factor. The participants of the qualitative interviews observed problems with wording and content of the items, especially from the social subscale. The general score correlated with other scales as expected. We found substantial variation in flourishing prevalence rates between the three cultural settings. Conclusions: The Danish MHC-SF produced reliable general scores of well-being. Most of the issues observed regarding the subscale scores have been shown in previous research in other contexts. The further analysis of indices of the bifactor model and the inclusion of qualitative interviews allowed for a better understanding of the possible sources of problems with the questionnaire's subscales. The use of subscales, the substantive understanding of the general score, as well as the operationalization of the state of flourishing, require further study.